> Are there any scripts that are always and only written vertically?
I think Mongolian script is always written that way.
Yes I think scripts like Mongolian and Phags Pa are always written vertically.
Are there any scripts that people actually write in
that people do not nowadays write horizontally in word processors?
I am sorry I do not understand the question, did you meant to say "vertically"?
btw word processors like libreoffice support vertical text.
If people have learned to accept writing those scripts horizontally, I
think that way is good enough for Emacs too.
Wouldn't it be better to support vertical text in Emacs, the only reason people would have "learned to accept" to write these scripts horizontally is because their preferred way of writing is not supported in many softwares/websites.
I know that this is a complex process, but at least we can try.